Cannabis compound 'could halt breast cancer'

Last updated at 11:28 20 November 2007

A chemical found in cannabis may stop breast cancer spreading through the body say scientists.

Researchers are hopeful that a compound found in cannabis called cannabidiol (CBD) could be a non-toxic alternative to chemotherapy. Unlike cannabis, CBD doesn't give users a 'high' and it is not illegal.

CBD works by blocking the activity of a gene called Id-1 which is believed to be responsible for the aggressive spread of cancer cells away from the original tumour site creating what are known as 'secondaries'.

Work has already shown CBD can block aggressive human brain cancers. The new research found CBD had a similar effect on breast cancer cells in the lab.

Lead researcher Dr Sean McAllister of The California Pacific Medical Centre Research Institute team said: "Right now we have a limited range of options in treating aggressive forms of cancer.

"Those treatments, such as chemotherapy, can be effective but they can also be extremely toxic and difficult for patients.

"This compound offers the hope of a non-toxic therapy that could achieve the same results without any of the painful side effects."

Doctors stress that smoking cannabis is unlikely to effective as sufficient quantities of CBD are not found in the leaf. They have to be extracted and are then concentrated to make a dose strong enough to kill cancer cells.

Dr Joanna Owens of Cancer Research UK said: "This research is at a very early stage. The findings will need to be followed up with clinical trials in humans to see if the CBD is safe, and whether the beneficial effects can be replicated.

"Several cancer drugs based on plant chemicals are already used widely, such as vincristine - which is derived from a type of flower called Madagascar Periwinkle and is used to treat breast and lung cancer. It will be interesting to see whether CBD will join them."